Aerofoil structure



July 5, 1938. A. s. BARKLEY AEROFOIL STRUCTURE Filed Jan. 14, 1937 5Sheets-Sheet 1 Z'mventor Hau /6142 p 5'. 3991 45 (Ittorneg y 5, 1938- A.s. BARKLEY 2,122,709

AERQFOIL STRUCTURE Filed Jan. 14, 1957 5 Sheets-Sheet 2 A. S. BARKLEYAEROFOIL STRUCTURE July 5, 1938.

Filed Jan. 14, 1937 5 Sheets-Sheet 3 Q! I I I I II x I /I II I I I I IIL/(II I I attorney July 5, 1938. BARKLEY 2,122,709

AEROFOIL STRUCTURE Filed Jan. 14, 1937 5 Sheets-Sheet 4 j Zhwentor fie/$ 60440 .3? 5398 11 4 (Ittorneg y 5, 1938- A. s. BARKLEY AEROFOILSTRUCTURE Filed Jan. 14, 1957 5 Sheets-Sheet 5 ATTORNEY.

Patented July 5, 1938 2,122,709

UNITED STATES PATENT OFFICE AEROFOIL' STRUCTURE Archiebald S. Barkley,Detroit, Mich assignor to Barkley-Grow Aircraft Corporation, Detroit,Mich., a corporation of Michigan Application January 14, 1937, SerialNo. 120,476

. 8 Claims. 244-123) This invention relates to airplane wing andbulkheads or ribs are necessary and the total control surfaces and hasfor its object to provide weight of the wing is substantially less thanthat improved all-metal wings and control surfaces. of the best previousall-metal wings of equal size More specifically, it isan object of thepresent and strength. invention to provide all-metal wings and controlHow the above mentioned and other objects surfaces lighter than butequal in strength and and results are attained will appear from the sizeto those made in previously known ways. following description and'appended claims, ref- Another object of this invention is to provideerence being had to the accompanying drawings wings and control surfacesin which thestresses, forming part of this specification, wherein likeinstead of being concentrated in a few spars and reference charactersdesignate corresponding 10 connections, are widely distributed, so that.any parts in the several views. small portion of a wing or controlsurface can be Figure 1 is a plan view of one embodiment of injured, asby gunfire, without seriously impairmy invention, showing a wing havingflaps and m ing the strength of the wing or control surface showing, indotted lines, a fuselage, ailerons and as a Whole. other details notforming a part of the wing Another object of this invention is toprovide itself. all-metal wings and control surfaces adapted to Figure 2is a front view of the embodiment be economically produced in quantity.shown in Figure 1.

It has been found, in all-metal wings, that Figure 3 is an enlarged planview of one of the structures of the same strength can be made wingsshown in Figure 1, a part of the wing 20 lighter in weight if parts ofthose structures carry being broken away to show the interior conmorethan one type of load, a'nd the tendency struction.

in design has been to design parts of the struc- Figure 4 is a frontview of the, wing shown tures so that they can carry a plurality ofdifferin Figure 3,

ent loads. For instance, in many all metal wings, Figure 5 is asectional view on line 5-5 of 25 the skin is smooth and carries part orall of the Figure 3, taken in the direction of the arrows. drag loads.In some few wings, the upper and Figure 6 is a front view of a secondform of lower skins, together with vertical webs joining the invention.1 them, also carry bending loads, and these wings Figure '7 is asectional view on the line 1---! of represent the most advancedpractical design Figure 3, taken in the direction of the arrows. 30prior to the construction and use of wings em- Figure 8 is a sectionalview on the line 88 of bodying my invention. However, in those wingsFigure 3, taken in the direction of the arrows. it is necessary toprovide local skin stiifeners Figure 9 is an end view on the line 99 ofspaced from and between the spars or webs and I Figure 3 taken in thedirection of the arrows. to provide rib-like diaphragms, bulkheads, orFigure 10 is a sectional view similar to Figure 35 other meansperpendicular to the spars to in- 7 but showing a third form of theinvention.

terconnect them and preserve the shape of the Figure 11 is a sectionalview of a fourth form wing section. of the invention.

. In a wing or control surface constructed ac- Figure 12 is an enlargeddetail view of the cording to my invention the skin stifieners spacedform of the invention shown in Figure 11. 40

from the webs connecting the skins together and Figures 13 and 14 areenlarged detail views of the diaphragms or other means extending beafifth form of the invention similar to the form tween and separate fromthe spars or webs can shown in Figures 11 and 12.

- be reduced in number or entirely omitted. The Figure 15 is a side viewof one form of web 5 elimination of these portions of the structuremember. formerly necessary is made possible by the use Figure 16 is anend view of the web member of a novel form of web structure whichsupports shown in Figure 15. the skins along enough lines to make manyor all Figures 17 and 18 are side views of other forms longitudinalintermediate stifleners unnecessary of web members.

and which, when combined with the skins, acts as One of the preferredforms of my invention, 50

a truss extending chordwise of the wing and reshown in Figures 1 to 5and 7 to 9 comprises a duces or eliminates the need for other chordwisewing, each half of which is formed of three stiffening means. When fulladvantage is taken sections A, B and C. The three sections A, B of mymethod of constructing a wing, no interand C are each formed oflongitudinally extendinediate longitudinal stlfleners nor chordwise ingsheets oi metal riveted together, although 55 they may. be welded. Thesheets forming each section overlap and are riveted or otherwisefastened to the sheets of the adjacent section, so that the sheets ofthe several sections form a single unitary structure.

At the root of the wing, as shown in Figure 7, the upper and lower skinsI3 and I3 areconnectecl by a plurality of web members I to 5 and I to5'. These web members lie between front and rear vertical web members III and II near the leading and trailing edges D and E of the wing. Theyare riveted to each other and to the skin to form a rigid structure.Each of the web members I to 5 and I to 5 has the general shape of aV-section trough with two wide sloplng portions :1. and b forming thesloping sides of the V-section. The sides a and b are joined together bya narrow horizontal portion c which is secured by rivets 6 to a similarflat portion of another web member, the two web members together formingan X-section. The edges of each of the web members I to 5 and I to 5'are bent to form narrow vertical portions e and 1, narrow substantiallyhorizontal portions 9 and h, and small vertical stiffening flanges 2'and 7'.

The X-sections formed by the pairs of web v members I and I, 2 and 2', 3and 3, 4 and 4',

and 5 and 5 extend side by side with their narrow vertical portions eand f in contact and secured together by rivets I. The narrowapproximately horizontal portions g and h of the web members I to 5 andI' to 5' lie against the inner sides of and are secured by rivets II tothe upper and lower skins I3 and I3 respectively. The narrow verticalportions e and f nearest the leading and trailing edges D and E of thewing are secured to the Web members I I.) and It by rivets I 2.

A web member 9 is secured between the portions e and) of the web members4, 4, 5 and 5' a little ahead of the trailing edge E of the wing.

Theweb member 9 extends along the wing just ahead of the flap I5 or, inwings having conventional ailerons-just ahead of the aileron and formspart of the means to which the flap or aileron is hinged, as shown inFigure 8.

The root sections A of the two halves of the wing are closed at theirinner ends with vertical flat plates I9 secured to the skin I3 of thewing by means of an angle member 23 and flush rivets 24. The ends of theweb members I to 5 and I to 5' in each half of the wing have flanges 25secured to the plates I9 by flush rivets 2G. The wing sections A arebolted either to each other or to a center wing section lyingbetween'them, depending upon the design of the airplane. In theparticular embodiment shown, the two sections are boltecl directly toeach other without an. intermediate center section, but a conventionalcenter section may be provided. In any case the connection is formed bybolts extending through holes 21 in the angle members 23 and end platesI9, or, if the end plates I9 are omitted, through the angle members 23only.

The web members I to i and I to 5 are preferably formed with flangedapertures 28 in their wide sloping portions a and b, as shown in Figs.and 16. The flanges 29 around the apertures project alternately inopposite directions as this has been found to result in greater strengththan if the flanges all project in the same direction. The apertures 28serve to lessen the weight of the structure and facilitate assembly.They also permit the passageacross the wing of conlengths of the paths.

for the ailerons I8, is provided by the longitudinally extending spacesbetween one web member and the next and between the web members and theskin. The aileron shafts I! are supported by suitable bearings (notshown) carried by the web members and by plates secured to the outerends F of the end sections C.

The fuselage 2| may be secured to the wings in any conventional manner,.as by being built onto a center wing section of conventional structurewhere such a section is used. In the embodiment shown, which is withouta separate center wing section, the fuselage is secured directly to theupper skin I3 of the wing by angles 22. If desired, the web members I to5 and I to 5 may be provided with stiifeners (not shown) directly underthe load applying members 22, the stiffeners extending across the webmembers and serving to distribute the load across them.

I6 near the leading and trailing edges D and E,

there are no vertical web members in the thickest part of the wingsection. In that part of the wing section, the only direct connectionsbetween the upper and lower skins I3 and I3 are through the wide slopingportions a. and b of the various trough-shaped web members I, I 2, 2, 3and 3'.

It is important that in the thickest part of the wing section, which isthe part which carries the greatest stresses, most of the distances fromone skin to the other measured along all the possible direct paths lyingon the faces of the web members be approximately the same. It isespecially important that none of such distances be substantially lessthan the majority of such distances. These points are important becausethe average shear stress in the metal on said paths, which can be termed"shear paths, is approximately inversely proportional to the Therefore,when a wing having the distances along some of such shear pathssubstantially shorter than the distances along the majority of the shearpaths is subjected to maximum load and the metal along the majority ofthe shear paths is subjected to approximately the maximum safe shearstress, the metal along the shorter paths will be subjected to a shearstress greater than the maximum safe shear stress and will fail. Alse,if a wing were built with some of the shear paths described above muchlonger than the majority of such shear paths, the metal along the longerpaths would be stressed far below the maximum safe shear stress andwould not be efflclently used, thus adding weight.

Besides forming an eflicient means for transmitting shear forces, asexplained above, the web structure cooperates with the skin to form atruss structure extending between the leading and trailing edges D andE. The web structure therefore maintains the .cress sectional shape ofthe wing and makes ribs or transverse bulkheads unnecessary.

Instead of making the wing in two sections, as shown in Fig. 1, or inthree or more sections, as is convenient for large airplanes, the entirewing can be made a single continuous structure, as shown in Fig. 6. Thistype of construction is especially suitable for the wings of smallairplanes or for other aerofoils of similar size, such as thestabilizers of large airplanes.

Another modification is shown in Fig. 10. In this form the web structureat any section of the wing is formed chiefly from two large sheets ofmetal 40 and 4| each formed into a series oi deep angular corrugationswith flat narrow crests c" and d". The two sheets 40 and 4| are placedwith their crests c" in contact with each other, and are securedtogether by rivets 6 to form a series of contiguous tubes having diamondshaped cross-sections. The edges of the sheets 40 and ll are secured toflat web members l0 and II by rivets i2. The web assembly is enclosed bythe skin l3 and i3 and the skin is secured by rivets I4 to the crests d"of the corrugated web members 40 and II and to the flanged edges oi; theflat and corrugated web members l0, ll, 40" and 4|. The structure thusformed is generally similar to the one illustrated in Fig. 7 andfunctions in substantially the same way.

The form of the invention shown in Figs. 11 and 12 is particularlysuitable for large wings. This form is generally similar to the formshown in cross-section in Fig. 8. However, the edges of the trough-likeweb members G, instead of being flanged and riveted to the skin closelyadjacent the points where they are riveted to each '50 and the regionsfrom which the edge portions 53 are bent back are secured by rivets 52to the similar regions 53 of the nextweb members. The row of rivets 5isecuring one edge 54 of one web member G to the skin 50 is at asubstantial distance from the row of rivets 5| securing the adjacentedge 54 of the next web member G to the skin 50. Also, the two rows ofrivets 5| securing the two edges of one web member G to the skin 50 aresubstantially closer than in the type of construction shown in Figure'7. This gives a more even spacing of the rows of rivets 5|, and theskin 50 is therefore better supported against buckling and can carrygreater loads.

To further increase the strength of the wing in bending, longitudinallyextending flange members 55 are placed between the skin 50 and theportions 54 of the web members G secured thereto. The flange members 56as shown on an enlarged scale in Fig. 12, are wide enough to extend fromone row of rivets 5| to the next and are of such a cross section thatthey will strongly resist buckling.

In the form of the invention illustrated by Fig. 11, the diagonal webstructure extends between vertical web members 51 and 58 near theleading edge and just ahead 01' the aileron or flap 59. The portions ofthe wing ahead of and behind the vertical web members 51 and 58 areformed by bending the skin around and securing it to short flanged andpierced rib members GI and GI secured to the vertical web members 51 and58. The aileron or flap 59, which may be of conventional structure. isin this case made similar to the wing shown in cross-section in Fig. 7.

A modification of a part of the wing shown in Figures 11 and 12 is shownin Figures 13 and 14, corresponding portions of the two forms of wingbeing shown in Figures 12 and 13. In the modiflcation, the web members Gdo not extend out to the skin 50 but are terminated just beyond the rowof rivets 52. The rivets 52 serve to secure together the edges of. twoadjacent webmembers G and the edges of two comparatively thick flangemembers 62. The other edges 0! the flange members 62 are spaced apartand are secured by rivets 5! to the skin 50. The flange members 62 thusperform the functions of both the flange member 56 and the portions 53of the web members shown in Fig. 12. The structure shown in Fig. 13 isnear the center of the wing where the bending load is greatest. As thetips of the wings are approached the flange members 62 become narrowerand lighter as shown in Fi 14.

The web members of any of the various forms of the invention may beformed in several ways. As shown in Figs. 15 and 16 in connection withthe form of the invention shown in Figs. 1 to 5 and 7 to 9, the webmembers may be provided with large flanged openings. The web members maybe flat and unperforated as shown in Fig. 17, or their wideportions maybe corrugated as shown in Fig. 18. In the latter modification, thecorrugations 63 extend across the web member and perpendicular to thelongitudinally extending uncorrugated regions 64 which are riveted toother members.

What I claim is: v

1. An aeroioil structure comprising an upper stressed skin, a lowerstressed skin, a spar near the leading edge oi. the wing, a second sparnear the trailing. edge of the wing, said spars being spaced chordwiseof the wing a substantial distance from the thickest portion thereof andtheir depth at any section of the wing being substantially less than thegreatest thickness of the wing at that section, and a shear transmittingweb structure lying between said spars and secured to said skins, saidweb structure consisting of intersecured longitudinally extending webs,said webs forming the walls of a series of adjacent Iour-comered andfour-sided tubular cells and cooperating with the skins to form a seriesof spaced three-sided and three cornered tubular cells along each skin,the upper corner of each of said four-sided cells being secured to thedepending corner of one of the three sided cells Iormedin part by theupper skin, the lower corner of each of said four-sided cells beingsecured to the upstanding corner of one of the three sided cells formedin part by the lower skin. and the lateral corners of each of thefour-sided cells be ing secured to the lateral corners of adjacentcells.

2. An aeroioil structure as described in claim 1 in which said webstructure consists entirely of said intersecured webs.

3. An aeroioil structure as described in claim 1 in which the lateralwalls of said three-sided cells are of stronger material than the wallsof secured to said skins and said lateral walls by said rivets.

6. An aerofoil structure as described in claim 1 in which longitudinallyextending reeni'orcing members lie at least partly within saidthreecornered cells, each of said reenforcing members being secured tosaid skin along two cornets of the cell containing it.

7.'An aerofoil structure as described in claim 1 in which longitudinallyextending reenforcing members lie at least partly within said threecornered cells, each of said reenforcing members being secured to saidskin along two corners of the cell containing it by means also securingthe walls of said cell to said skin.

8. An aerofoil structure as described in claim 1 in which laterally bentlongitudinally extending reenforcing members lie at least partly withinsaid three-cornered cells, each of said reenforcing members beingsecured to said skin along two corners of the cell containing it.

ARCHIEBALD S. BARKLEY.

